Applicant's prior U.S. Pat. Nos. 3,162,487 and 3,162,488 disclose under-body ventilating seat cushions which have protuberances formed in sheets of plastic material, which protuberances coact with other elements of the seat to space a body above the supporting surface. The sheets of plastic material in these patents depend in good part on inherent stiffness of the plastic sheet to resist objectionable flexure in use thereby requiring expensive heavy gage sheet material. The seat cushions of these patents require additional elements, including perimeter stiffening devices and reinforcing sheets in addition to the usual covering material on the seat cushion.
In addition to the foregoing described disadvantages, known seat cushions of the prior art were too flexible to adequately support the body, deforming excessively and thereby decreasing the ventilation through the seat as well as providing less support to the body. Some prior art seat cushions have complex constructions making them expensive to manufacture. Other prior art seat cushions achieved resilient support by the use of metallic springs which are expensive and such cushions usually required frames.
Applicant has desired to develop an all plastic seat cushion that would not necessarily have to have fabric covering it nor reinforcing sheets embodied in it. Applicant also has desired to develop an all plastic seat cushion that would have some spring action and an all plastic seat cushion that would eliminate the necessity of perimeter stiffening devices.